Today, one of the most rapidly growing markets for computer systems is the portable computer market. Recently, portable computers have become more powerful, while also becoming smaller and lighter. Furthermore, as a part of this changing market, various computer components have become smaller and lighter while their ability to handle more data has increased.
One group of devices which is especially important to portable computers is peripheral input/output devices such as paging receivers, modems, facsimile machines, or local area networks (LANs). A paging receiver, for example, allows a user of a portable computer to receive messages that are broadcast over wide areas. The paging receiver receives paging messages through an antenna and generally stores the paging messages on board for retrieval through the computer system. The reduction in size of paging receivers occurred at the same time as the reduction in size of other components, such as hard disks.
Typically, electronics for computer, such as that of the paging receiver, are arranged on an internal board within the computer. Some arrangements provide separate portable electronics which will be carried along and attached to a portable computer when needed. Furthermore, some electronics, paging receivers in particular, have been designed recently to plug into sockets recessed within the body of a portable computer. Various forms of computer components may be plugged into the same socket of a computer, thereby reducing the space required within the portable computer. For example, an international standard which defines the physical and electrical interface specifications for the interchangeability of memory and input/output cards was introduced by Personal Computer Memory Card Internationally Association (PCMCIA) concurrently with the Japanese Electrical Industry Association (JEIDA) in September of 1991. These cards are often referred to as integrated circuit (IC) cards.
The PCMCIA specification provides its personal computer cards be a specific size (with respect to its outer dimensions) and to include a 68-pin connector located at the end of the card for the sending and receiving of signals between the card and the computer system.
A side-section view of the standard assembly for a PCMCIA card is shown in FIG. 1. Referring to FIG. 1, PCMCIA card 100 is shown with top cover 101, backfill 102, printed circuit (PC) board assembly 103, frame 104, backfill 105, bottom cover 106 and end cap 107. Top cover 101, bottom cover 106 and frame 104 provide the outer protective structure of PCMCIA card 100. Top cover 101, bottom cover 106 and frame 104 act to protect the components on PC board assembly 103. Frame 104 supports PC board assembly 103 while top cover 101 and bottom cover 106 enclose the remainder of card 100. Top cover 101 and bottom cover 106 are typically comprised of stainless steel. Frame 104 is usually made out of plastic.
PC board assembly 103 contains the electronic and integrated circuit components used to provide the functionality of PCMCIA card 100. For instance, the components on PC board assembly 103 may allow PCMCIA card 100 to act as a paging receiver, a modem, a LAN access or one or more of a variety of other functions. In one embodiment, PC board assembly 103 includes a mating connector 103A for interfacing with the computer system (e.g., notebook or laptop computer system). PC board assembly 103 also includes PC board 103C which couples the electronic components in board assembly 103 together. If PC board assembly 103 is to act as a paging receiver, an antenna 103B may also be coupled to PC board 103C to receive paging messages. End cap 107 holds the entire structure together by sliding over the ends of top cover 101 and bottom cover 103 when they are in contact with frame 104.
One problem with prior art PCMCIA card assemblies is that they did not adequately protect the circuit components on PC board assembly 103. Because the size (i.e., thickness) requirements of the card and the size of the circuit components, the metal used for top cover 101 and bottom cover 106 is usually thin. Since the metal is thin, it is easy to depress top cover 101 and bottom cover 106 into the card and damage the circuit components when handling the card. One prior art solution to this problem was to provide backfill 102 and backfill 105 to the standard assembly of PCMCIA card 100, as shown in FIG. 1. Backfills 102 and 103 are typically lexan plastic sections designed to provide added support and protection to the components on PC board assembly 103 by preventing top cover 101 and bottom cover 106 from being depressed into the card interior. One problem of using backfill 102 and backfill 105 is that the plastic must be molded to the specific configuration of the components on PC board assembly 103. Therefore, if changes are made to the components on PC board assembly 103, backfill 102 and backfill 105 may have to be redesigned. The redesign may require producing another mold by which the plastic backfills 102 and 105 are made. It is desirable to produce the PCMCIA card which protects the circuit components on the PC board assembly 103 without having to use backfill sections. Moreover, it is desirable to produce a outer support structure for PCMCIA card 101 that can be used for all types of circuit component arrangements on PC board assembly 103, such that any change in the circuit board assembly does not result in changes to the outer support structure.
One possible solution to strengthening the outer structure is to utilize a thicker metal structure for top cover 101, bottom cover 106 and frame 104. On one hand, the thickness of the metal is limited by the requirement of the PCMCIA standard that the cards be of a certain thickness. Furthermore, in certain applications, PCMCIA card 100 cannot utilize a metal outer structure. For instance, if PCMCIA card 100 is designed to be a paging receiver, an antenna is required for receiving paging messages. This antenna would be located within PCMCIA card 100. A metal outer structure would interfere with the antenna's ability to receive the paging messages. Therefore, a metal outer structure cannot be used for all applications of PCMCIA cards. Therefore, it is desirable to strengthen the outer structure without having to use a metal or conductive outer structure.
Another problem associated with the PCMCIA cards that utilize backfill components 102 and 105 is the added cost that is required. Prior art PCMCIA cards using backfill can cost around $4.00/piece to produce. This cost is generally considered high when compared to the cost of the circuit components on PC board assembly 103. It is desirable to produce a PCMCIA outer protection structure which is less expensive than the prior art.
The present invention provides an assembly configuration for a PCMCIA card. The present invention provides an outer support that protects the components on the PC board assembly while not requiring backfill components in the assembly. Furthermore, the present invention provides an outer support structure for a PCMCIA card that does not interfere with an on-board antenna. Furthermore, the present invention provides an assembly for PCMCIA card that may be produced at a lower cost than prior art PCMCIA cards.